• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.207-210
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• 2001

Electrical equipment for railway is always experiencing wear and degradation by mechanical, electrical and environmental stress in service and the fault or the accident of high voltage main circuit directly causes operation interruption. Particularly propulsion drive of high speed switching inverter takes the form of specific degradation mechanism such as fast rising transient surge, reflective overvoltage and harmonic stress, and it is known that it threatens the long life and the reliability of electrical equipment. In this paper, statistics of fault and accident on main electrical equipment for railway are presented and also insulation degradation mechanism, which governs end life of electrical device, is analyzed. Finally the method of fault respondence and reliability improvement on the main electrical equipments will be reviewed in order to prevent operation interruption.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.329-330
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• 2006

The purpose of this paper is to compensate the voltage drop of the power system in the AC Electric Railway Systems. Reactive power compensation is often the most effective way to improve system voltage drop. The suitable modeling of the electric railway system should be applied to the EMTP. the dynamic characteristics of 3-Phase Induction Motor in Electric Railway Systems is considered for precise modeling. it is shown through EMTP simulation using EMTP MODELS that voltage drop can be compensated effectively by STATCOM.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.646-652
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• 2015

Increasing needs for rapid driving vehicles during rush hour, there are various researches how to operate or allocate rapid driving vehicles with the existing normal driving vehicles. In the aspect of power system, it should be preceded by an analysis for power equipment capacity. Also, it should be studied whether the added rapid driving vehicles gives a bad effects for stable operation of railway systems or not. In order to derive the results for these analysis processes, this paper suggest a novel analysis algorithm which can implement integrated analysis including rapid and normal driving railway vehicles simultaneously. This algorithm has been verified using Seoul Metro 7 Line data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.191-196
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• 2014

For the large scale of electricity consumer, since the price for the electricity consumption depends on the peak power, the issue for peak power reduction have been being studied widely. Electric railway systems, which is one of the most representative large scale of loads, also has assignment to reduce the peak power since they have high peak power and low energy consumption load characteristics. In the aspect of the economic operation through reduction of peak power, this paper proposes a novel algorithm for power management system in electric railway systems using energy storage.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1457-1465
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• 2016

A RCM approach to maintenance of the catenary system of electric railway is proposed. The proposed RCM approach provides a maintenance-oriented FMECA procedure to derive critical failure modes by analyzing failure effects and a RCM decision logic tree to suggest optimal maintenance works for the derived failure modes. By applying the proposed RCM procedures to the catenary system of high speed railway, it is suggested that strand breaks of dropper and voltage equalizing wire, and trolly wire wear-out are the critical failure modes for whom maintenance works based on condition monitoring should be applied instead of conventional time-based preventive maintenance. It is also proposed by reliability analysis that replacement time of dropper can be reduced from 18 years to 10 years. These results show that the proposed RCM approach can optimize the maintenance procedures of catenary system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.895-901
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• 2016

Nowadays, the axle counter has been developed to the wide range of the track circuit blocks as well as the wheel detection device. The axle counter, as becoming an important device for the high speed railway, must be guaranteed in accordance with the safety. With considering the safety and the high speed, performance evaluation a wheel detection sensor is described in this paper. To increase the safety, digital proximity sensor instead of analog is employed in the wheel detection sensor. Therefor the wheel detection sensor can minimize noisy signals caused by the harsh railway environments. And, to meet the high speed railway requirements, the performance of the wheel detection sensor is also successfully verified using the speed simulator at the velocity 500Km/h.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.268-274
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• 2010

Urban rail transit brings the benefits of various aspects of society. With the advent of fast and large trains, however, risk and scale of accidents have increased. Despite the fact that there is various safety features built into the modern metros, train faults happen from time to time. Especially, as urban railway vehicles in Korea have become deterioration rapidly, more advanced diagnosis methods are required to prevent various accidents. In this paper, we present diagnosis method for electrical wires to guarantee secure driving and authenticity more accurately in urban railway vehicles. Although there are kinds of conventional methods based on insulation resistance measurement and withstand test, it is extremely difficult to effectively diagnose obsolete equipments such as electrical wires and cables not new ones. This study is focused on development of diagnosis method and establishment of evaluation standard for electrical wires in urban railway vehicles.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1796-1803
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• 2015

Unlike commercial LTE network, LTE-R railway network is arranged along a railroad track and the base stations of the network (RUs) are also installed on the waysides. For urban railway systems that are composed of underground tunnels, the leakage coaxial cables are widely used due to the radio propagation characteristics in tunnels. In theory, the tunnel sections are interpreted as the waveguide with blank spaces and for this reason, the tunnel sections are expected to be better than open ground sections in terms of the radio propagation characteristics. In this paper, we analyze the radio propagation characteristics based on this theory by replacing the leakage coaxial cables in the network with Yagi antennas. The test has been carried out in the 2.2km tunnel in the Daebul test track of KORAIL with 2.6GHz LTE-R Network. The LTE-R applicability in urban railways has been tested through the analysis on the radio propagation characteristics with the unmanned train operation system in Daebul tunnel.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.2
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• pp.95-100
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• 2009

Recent advances in computer technology have brought more dependence on software to railway systems. Hence, the safety assurance of the vital software running on the railway system is very critical task and yet, not many works have been done. While much efforts have been reported to improve electronic hardware's safety, not so much systematic approaches to evaluate software's safety. In this paper, we suggested an automated analysis tool for S/W change impact in railway system, and presented its result of implementation. The analysis items in the implemented tool had referred to the international standards in relation to the software for railway system, such as IEC 61508 and IEC 62279. In these international standards, 'change impact analysis' for railway system S/W has to be required mandatorily. The proposed tool can be utilized at the assessment stage and also the software development stage.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1905-1909
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• 2008

As catenary supply electric power directly to the railway system, it is very important to prevent an accident of a catenary for appropriate train operations. This paper analyzed the outage data for British catenary safety analysis report and Korean data to compare the reliability of the railway systems. The analyzed data were applied to Fault Tree Analysis(FTA) algorithm to calculate the reliability indices of a railway system. Failure rate of an electric railway system through FTA were calculated for each element and the entire railway system. The reliability indices can be used to determine the eqipment to be replaced for the entire system reliability improvement.